The Blue Bag Of Hoarding was originally found by Urist, Eyrun & Jules inside of the Abominable Yet's Cave on the Cloudfire Mountains. It looks like a large bag, just happens to be blue, and most people would confuse it with being a “Bag Of Holding.” This is however not the case, as it is instead a “Bag Of Hoarding.”
Simply put it functions as a Bag Of Holding would except that:
It is sentient and talks when appropriate to make sure that it is only used for placing high value hoards into itself.
If anything is to be taken out of the bag, a high value hoard must be placed in the bag to make it willing to allow anything out.
“High Value” in this case means single items of great value or large amounts of misc things (mixed variety is okay) that in sum are worth a lot. e.g. A thousands of gold, a potent magical item, a collection of gemstones.
As a stipulation any time a player opens the bag to use it they must roll a 1d10. On the result of a 1, something different happens. The outcome of which has not yet been disclosed in a game session.